Maintenance of railroad track and replacement of railroad ties requires the removal of spikes from the ties to permit separation of the track from the ties and the positioning of new ties. Removal of the spikes is also required to permit replacement of worn or damaged rails or replacement of joined rails with continuous lengths of rail welded together.
One of the prior art methods for use in removing the spikes from the ties and ties plates requires the use of a pry bar having a split claw on one end, and conventional spikes having an offset head are manually pried out of the ties by means of this tool.
Machines have also been constructed for mechanically pulling such spikes out of the ties. Such machines commonly include a clamping assembly, including a pair of jaws movable toward and away from each other and operable to grip the offset head of the tie spike. Mechanical structure is provided for then lifting the clamping assembly so that the spike is pulled from the tie and the tie plate. This lifting structure can be either a hydraulic cylinder or a mechanical lifting device.
One of the problems with such prior art spike pulling machines is that in many cases two operators are required, one to operate and guide the clamping device on one side of the rail and another operator to guide the clamping device on the other side of the rail. Another problem with the prior art spike pullers is that they are not designed to pull hairpin spikes, but are only designed to pull conventional spikes having an offset head.
Hairpin spikes have a head consisting of a metal loop defining a loop-aperture, which is above the surface of the tie and the tie plate, with a shank consisting of two legs which are embedded in the tie. Such spikes currently must be removed from the tie by the use of a manual pry bar having a hook on the end which fits through the loop-aperture of the hairpin spike. Attempts at automating the removal of hairpin spikes have resulted in relatively cumbersome machines requiring separate powered mechanisms for grasping the spike and for holding the spike during withdrawal.
Accordingly, it is an object of the present invention to provide an improved spike pulling tool for removing hairpin spikes from a railroad tie.
It is another object of the present invention to provide a hairpin spike pulling tool which may be integrated with a spike pulling machine for removing hairpin spikes from railroad ties in a facile manner.
It is a further object of the present invention to provide a hairpin spike pulling tool which can be machine operated to grip the loop-shaped head of the hairpin spike with no manual assistance by the machine operator, or by others in the track repair crew.
It is yet another object of the present invention to provide a hairpin spike pulling tool which is readily interchangeable with conventional spike pulling tools on a conventional spike pulling machine.
It is still another object of the present invention to provide a hairpin spike pulling tool which grasps and holds the spike without supplemental power mechanisms.
These and other objects of the invention, as well as the advantages thereof, will become more clear from the disclosure which follows.